"All these airports are capable of handling medium capacity-range, long-range type aircraft and are also equipped with facilities for night operations," Finance Minister P Chidambram told reporters after the meeting of Cabinet Committee on Economic Affairs here.

He said the airports have been upgraded to the international standards and "this declaration is expected to provide impetus to domestic or international tourism and contribute to economic development of the concerned regions."

There are 454 airports and airstrips in the country, of which the state-run Airports Authority of India (AAI) owns and manages 97 airports and 28 civil enclaves at defence airfields.

So far, 16 of them have been designated as international airports while several other airports had been designated as 'Limited International' for a restricted number of global flights from there.

Conversion of a domestic airport into an international one primarily entails creation of immigration facilities and deployment of manpower to carry out these tasks. The government plans to have 500 operational airports by 2020 and aims to attract private investment in aviation infrastructure to meet this end.

The Lucknow airport is suitable for all-weather operations and can provide parking facility up to 14 aircraft. At present, Air India, Jetlite, GoAir, IndiGo and SpiceJet are operating domestic flights from and to Lucknow.

Varanasi airport is also an all-weather facility and the existing apron can accommodate five Boeing 767 and four Airbus 321 aircraft. Air India, Thai Airways and Cosmic Air are operating international flights from there.